Sidewall sampler



444 MA A A va' ww March 15, 196@ K. H. MINER 2,928,658

SIDEWALL SAMPLER Filed June 25, 1956 :s Sheets-Sheet 1 4 57 A/. M/A/Ee INVENTOR.

March 15, 1960 K. H. MINER 2,928,553

SIDEWALL SAMPLER Filed June 25, 1956 s Sheets-Sheet 2 4 5/74 h. M/A/Ee INVENTOR.

arrow/5g SIDEWALL SAMPLER Keith H. Miner, Newport Beach, Calif., assig'nor, by.

mesne assignments, to Dresser Industries, Inc., Dallas, Tex., a corporation of Delaware Application June 25, 1956, Serial No. 593,741

14 Claims. (Cl. 255-1.4)

State atefi.

These andother more specific objects of the invention willbecome apparent from the following detailed specifij cationand. appended claims, and from the drawings ata borehole of the minimum size required for the essential.

operating tools; From time to time it becomes desirable toexamine and test specimens of the earth formation or crust to determine the presence of certain elements as a guide for further operations. This necessity gives rise to the problem ofobtaining expeditiously specimens of a size suitable for-testing. The recovery of boring chips for this purpose is unsatisfactory because of the small ness of the chips, the difliculty of retrieving them, and particularly because they are obtainable only fromthe bottom of the borehole. Another mode of recovering samples avoiding the described objections to the use of boring chips involves cutting a specimen from the borehole wall by projecting a captive core sampling device such as a hollow tubular projectile into the wall by an explosive charge, and thereafter retrieving the sampling device and the specimen contaiued therein.- 'While this practice has met with considerable success and is superior to other sampling pro cedures, it has several objections obviated by the presentinvention. For example, the size of specimen recoverable tached thereto and forming a part thereof.

Referring now to the drawings in which a embodiment of the invention is illustrated:

Figure 1 is an elevational view of a sample recovery apparatus incorporating the present invention, with certain parts shown in section;

Figure 2 is a fragmentary. elevational' view along the: plane designated 2-2 on Figure 1, and showing the ar--: rangement of the-samplesevering assembly relative to: the sample recovery means;

Figure 3 is a longitudinal sectional view through the slug-firing unit and the sample-severing assembly and indicating by dot and dash line how the sample is severed and held captive; 1

; Figure 4 is a transverse sectional view taken along line. 4-4 on Figure 3; and

. Figure 5 is a view similar to Figure 3 showing an alternate arrangement of the flexible sample recovery cable.

Referring to the drawings and particular to Figures 1 preferred:

. to 3, it will be seen that in a preferred embodiment, the

' respectively .to cable head assembly 11 and to a thick islimited by the size of the sampling device and of the,

propelling gun which can be employed in a particular sizeborehole; Furthermore, in many formations it is diflicult to free the sample and its surrounding cutter from the earth formation without breaking the retrieving cable."

wall by an explosive charge.

walled gun tube 18 supporting the explosive charges to be: described presently and employed to sever a sample of theborehole wall for recovery to ground level.

As is best shown. in Figure l, the connection of gun: tube 18 to coupling 17 is employed to firmly clampa disk: 20against a shoulder of the coupling member, the periphery ofthe disk being provided with an O-ring 21 or other suitable resilient means for sealing the central chamber of the coupling against the entry of fluids. Extending 1 through disk 20 in a fluid-tight manner is a pair of inably' shortly thereafter, one or nioreshaped charges are L discharged in such manner that their fluid jets are -efiec-- tive to dislodge'a sample from-the surroundingearthformation for withdrawal to ground level by the'aid of the flexible cable held fixed therein by the slug.

In view of the foregoing, it is a primary-object of this invention to provide a new and superior method of recovering a sample of the earth formation from any deL- sired'point'within the depths of an earthborehole.

Another object of this invention is to provide a simple l and reliable device which can be lowered into aborehole along a'borehole:

More specifically, it is an object. of thisinventionto sulated electrical terminals 22, 23 having their inner ends connected by suitable wires 24 to terminals'15 and- 16 respectively, the latter terminals being accessible from the exterior of coupling 17 through a removable fluidtight plug.25. a

It will be understood that gun body 18 may be and pref erablyisp'rovided with a plurality of sample-procuringstations 30 located along the body and opening radially through its side wall. Since these stations are similar in constructiononly one has been illustrated. Each station is located in a cut-out 31 in the side wall of tube 18.

Firmly secured to the interior wall of the tube opposite opening 31 is a heavy-walled tube 32 having one end terminating in a plane parallel to the axis of the gun body. Threadedly received in the end of the tube 32 is the casing 33 of a high-powered gun having a short gun barrel 34 threaded into its outer end and cooperating to provide a chamber 35 for an explosive charge 36, the rear end of the latter being seated against an igniter 37.

I Encircling explosive charge 36 isa high-strength flexibleprovide. .a: procedureifor attaching a:. recovery; line to J a cable 38 having its inner end secured to the wall of the cavity as by welding 39 and its forward end swagged-into" a cavity at the rear end of a slug or projectile 40 havinga close sliding ,fit in the bore of gun barrel 34, preferably closed .at its forward end by a sealing plug 41. v NJ Igniter 37 being of the type fired electrically, the rear' ofgun casing 33 is provided with a bore for an insulating sleeve and an electrical conductor 43 threaded at its outer end so that the insulated conductor Wire 44 can be clamped thereto in accordance with conventional practice.

As will be recognized, the slug gun is of the. type which may be re-used repeatedly, the recharging being accom' plished .by removing barrel 34 and inserting anew .detonator and explosive charge, care being taken. to wrap the flexible cable 38 about the charge and to replace. the slug 40 within the barrel bore as the barrel proper is threaded home within the seat provided at the forward end of the gun casing. 1

Surrounding the outer end of the slug gun assembly is a thick frangible ring 48 having a series of sockets 49 each seating a shaped charge unit designated generally 50. Mounting plate 48 may be secured in opening 31 of the tubing gun as by cap screws Sit-(Figure 2). As is made clear by Figure 3, the shaped charge units 50 are arranged concentrically about the axis of the slug-gun with the axes of the shaped charge units converging toward the axis of the gun, the point of merger being spaced six to ten inches forwardly of the end of barrel 34, as indicated in Figures 3 and 4. It will be understood that the point of convergence may vary widely depending on the size of the shaped charge units, their radial spacing from the axis of the gun, the borehole depth at which the gun is, being employed, the characteristics of the rock formation, and like factors.

It will be noted from Figure 3 that sockets 49 for the. shaped charge units extend through frangible ring 48. to, expose the transverse openings 52 through which extend the Primacord 53 or other suitable firing arrangement for firing the detonator 54 seated in a recess 54a formed within the frangible casing 50a of each shaped charge unit. One end of detonator 54 is in contact, with Primacord 53 andits other end is surrounded by the main explosive charge 55 of each unit 50, charge 55 being retained within the unit casing 50a by the usual conical liner 56. Closing the discharge end of units 50 in a fluidtight manner is a suitable domed cap 57 designed to withstand the high fluid pressures encountered in deep boreholes. This cap not only withholds the fluids from the-interior of the shaped charge, but provides an essential and suitable low pressure stand-oft space between the apex of liner 56 and cap 57, thereby providing an opportunity for the high velocity jet to form before. encountering high resistance andmaterially increasing the efiiciency and effectiveness of the shaped charge units.

It will be understood that the Primacord or other igniter' forxdetonator 54 extends between the shaped charge units mounted in ring 48 and terminates at one end in a blasting cap 59 of the type adapted to be fired. electrically. To

this end, the cap has a pair of electrical conductors 60 sample of rock formation from the sidewall of the bore-.

hole. Each of these stations is preferably disposed along one side of the tube so as to overlie an opening. 64 immediately below the lowermost of the firing stations 30 for the purpose of providing a. chamber to receive the 7 samples of rock formation severed from the bore wall and protecting these samples while they are being withdrawn to the surface. A typical sample of rock formation 65 is illustrated in dot and dash lines in Figure 3, it being noted that this sample is held captive on a flexible eable 38, the central portion of which extends through a: longitudinal grooveway 66 in the outer surface of the V gun body to protect the cable from damage from com tact with the wall as the apparatus is being retracted from the borehole.

The manner of using the apparatus to sever a sample will be readily apparent from the foregoing description. The first step is to prepare the apparatus by loading each of the slug guns and by filling recesses 49 with sealed shaped charge units 50 and connecting each in circuit with sections of explosive Primacord 53, a blasting cap 59, and igniter wires 44, 60, 61 in the manner described. If there is more than one firing station and it is desired to obtain more-than one rock formation sample, each station is prepared in'the same manner after which the assembled sampling apparatus is lowered into a borehole to the desired depth and fired by closing the electrical circuit to fire igniter 37 for the slug gun and blasting cap 59. The explosion of the propellent charge 36 projects slug 4%) into the rock formation as the flexible cable 38 is uncoiled and extended through the gun barrel to provide a high strength tie between the rock formation and the gun tube. Likewise, the firing of the shaped charge units operates in known manner to project high velocity jets of gas through the surrounding well fluid and into the rock to form converging cavities 67. The formation of cavities 67 in the manner described is effective to sever a conical sample of rock from the sidewall without the necessity ofthe apexes of the cavity 67 actually merging with one another either at their apexes or along their adjacent sides. While the reasons for this are not clearly understood, it is believed that the high velocity jets of the gas forming cavities 67 set up shock waves which cooperate to. sever the rock in a manner to dislodge an integral and generally conical sample of the rock formation. If this shattering of the rock is incomplete, it is found that the retraction of the gun acts through the flexible cable 38 to complete dislodgement of the sample. In some formations a greater number of shaped charge units are found desirable in assuring dislodgement of a sample. In this. event a frangible ring 48 having provision, for supporting a greater number of shaped charge units is employed. Following dislodgement of the samples and slight withdrawal of the gun apparatus, the samples work their way past the side wall of the gun and into the pocket provided within tube 18 immediately below opening 64. In the alternative, the samples may hang suspended on their respective cables 38 the mid! portions, of which are confined within the longitudinal groove 66 of the gun tube to prevent crushing and severingof the cables as the gun is being wtihdrawn.

Referring to Figure 5, there is shown in fragmentary form the firing station 30 for an alternate embodiment of the; invention differing from that described above in the use of: a slightly modified slug gun wherein the flexible sample recovery cable is stored about the exterior of the gun barrel rather than in the propellent chamber. In view of the close relationship between the structural parts of the alternate embodiment and those in the first described embodiment, the same, or similar parts have been designated by the same numerals and distinguished by the use of a prime; The principle structural diiference between the .two embodiments resides in the use of a modified gun barrel 34' and a modified slug 40. It will also be observed that the, sample recovery cable 38 has one end anchored, to, the side of the slug and its other end anchored to the exterior of gun casing 33' at a'point adjacent the base of barrel 34'. This arrangement permits thecable to be wrapped about the exterior of barrel 34 where it is protected against damage from the exploding charge 36' used to propel slug 40' into the rock formation.

The embodiment of Figure 5 is employed in exactly the, same manner described above in connection with. Figures 1, to 4 and is effective to dislodge a sampleof rock from the bore sidewall and to retain the sample captivein the manner. aforedescribed.

It willbe understood-that inthe. use. of either embodi+ ment of the invention, the firing of the charges results in the complete shattering and total destruction of units 50 and 50' as well as of the frangible supporting rings 48 and 48'. Substantially all portions of these shattered members are retained within gun tube 18 for removal and appropriate disposal after the gun has been withdrawn from the borehole. Any debris remaining within the borehole settles harmlessly to the bottom of the hole. The described sample recovery apparatus is restored to use by mounting a new set ofshaped charge units in a new supporting ring, connecting the detonator cord 53 between the units and then securing the ring in opening 31 by the use of cap screws 51. The slug gun is also reloaded with a fresh propellent charge after removing barrel 34. If the slug has beemdamaged in firing, it is replaced with anew one; otherwise the same slug is restored to its closely coiled position in the propellent chamber and the barrel is screwed back into the gun casing.

While the particular sample recovery apparatus herein shown and described in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

I claim:

1. A sampler for obtaining a formation sample from a borehole comprising: a body member adapted to be lowered into a borehole; means mounted on said body member utilizing a plurality of shaped charge units for severing a sample from the bore wall; and means for projecting one end of a flexible attachment member into said sample the other end of the cable being attached to said body member, whereby the raising of said body member effects the lifting of the sample to ground level.

2. A sampler for use in severing and recovering a formation sample from a borehole comprising: an elongated body member adapted to be lowered into a borehole, projectile means operatively associated with said body member; means carried by said body member for firing said projectile means into the borehol wall; a flexible attachment member having its opposite ends anchored respectively to said projectile means andto said body member; explosive shaped charge means mounted on said member and arranged when detonated for dislodging a sample of the formation into which the projectile means is adapted to be fired; and means for firing said projectilefiring means and detonating said shaped charge means thereby to dislodge a sample from the borehole wall and hold such sample captive on said attachment member.

3. A device for obtaining an earth formation sample from a substantially liquid-filled borehole which comprises: gun means adapted to be lowered downwardly into a liquid-filled borehole; means including an explosive charge for securing the end of a short flexible attachment member at a point to the borehole wall; means securing said flexible attachment member to said gun means for withdrawal from the borehole; and means supported on said gunmeans for separating from the wall of the borehole a portion of earth formation around said point and having said flexible attachment member secured thereto. i

4. A device for obtaining an earth formation sample from a borehole of a diameter conventionally formed by a unitary power-driven drill bit assembly, said device comprising: -a heavy-walled tubular gun means; a slugto said gun means, the firing of said slug-propelling charge being effective to propel said slug into a portion of the earth formation and thereby anchor said cable to the sample for removal of the latter to the earth surface upon the withdrawal of said gun means; and means supported on said gun means for separating from the wall ofjthe borehole such sample portion of earth formation around said slug. V s

5. A device for obtaining an'earth formation sample as defined in claim 4 wherein said cable is coiled behind said slug and in a chamber containing said slug-propelling charge of explosive. p

6. A device for obtaining an earth formation sample as defined in claim 4 wherein said cableis coiled about said slug'exteriorly. of the chamber containing the slugpropelling charge of explosive. I

S 7'. 'In combination, a sidewall sampler device comprising: a tubular member adapted to belowered into a borehole and having an opening through its side wall; gun means supported in said opening in said member hav ing a barrel extending crosswise of the member and adapted to project an earth-formation penetrating slug into the sidewall of a borehole through said opening; a slug operatively associated with said gun means; flexible cable means anchored to said slug and to said sampler device; and shaped charge means arranged closely around said gun means and aimed through said opening to project high velocity fluid jets into a borehole side wall convergently along an axis traversing the axis of said gun means and around said slug after penetrating a borehole sidewall to dislodge a sample of earth formation having such slug embedded therein, whereby the dislodged sample is held captive by said cable as said sampler device is withdrawn from a borehole.

8. The combination defined in claim 7 including a plurality of shaped charge means arranged about the discharge end of said gun means and having their axes converging on the axis of the gun means in a zone spaced outwardly from the wall of the borehole and within the earth formation.

9. A sampler for obtaining a formation sample from a borehole comprising: a body member adapted for lowering into a borehole; projectile means operatively associated with means mounted on said body member for impelling the projectile means into a borehole formation; an attachment member establishing a connection between said body member and said projectile means for retrieval of the latter from the borehole; and shaped charge means mounted on said body member for severing a portion of the borehole formation including the projectile means impelled thereinto.

10. A sampler for obtaining a formation sample from a borehole comprising: a body member adapted to be lowered into a borehole; an outwardly directed gun barrel in'said body member; a projectile in said barrel; an elongated flexible attachment means interconnecting said projectile and said body member; means for propelling said projectile from said gun for l-penetration into a surrounding borehole wall while remaining attached to said flexible member; explosive shaped charge means supported by said body member and arranged, when detonated, to dislodge a sample from the adjacent borehole wall into which said projectile is directed for penetration.

11. The method of procuring a sample of earth formation from a borehole which comprises: firing a projectile into the earth formation from a position within a borehole velocity jets of gaseous material into the earth formation firing means opening through the sidewall of said gun means; slug-propelling charge of explosive operatively associated with said slug-firing means; a slug operatively associated with said slug-firing means; a relatively short flexible cable coiled about the longitudinal axis of said slug; means for securing one end of said cable to said slug and for anchoring another portion of said cable in a peripheral pattern around and exterior of the embedded projectile to dislodge a sample of the formation containing the projectile, and retrieving the projectile and dislodged sample adhering thereto.

12. The method of procuring a sample of earth formation from the sidewall of a borehole which comprises: firing a captive projectile into the sidewall to embed the projectile therein; subsequently projecting a plurality of high velocity gas jets into the sidewall in a peripheral pattern around the embedded projectile to form an annu- Iar ruptured pattern in the formation around the em: bedded projectile and defining a sample body adhering thereto; and withdrawing the captive projectile and the adherent sample body from the sidewall.

13. The method of procuring a sample of earth formation from the sidewall of a borehole which comprises: firing a captive projectile into the sidewall to embed the projectile therein; subsequently projecting a plurality of convergently directed high velocity gas jets into the sidewall in a peripheral pattern around the embedded projectile to form a ruptured annular pattern in the sidewall around the embedded projectile and defining a frustro-conical formation sample adhering around the projectile; and withdrawing the projectile'and adherent sample firom the sidewall.

14. The method of procuring a sample of earth formation from the sidewall of a borehole which comprises: embedding a captive projectile in the sidewall; directing a plurality of high velocity gas jetstinto the sidewall in a peripheral pattern to fracture the earth formation and define a sample plug around the projectile; and withdrawing the projectile from the sidewall thereby detaching the aforesaid sample plug adherent to the projectile from the sidewall.

References Cited in the file of this patent UNITED STATES PATENTS 12,055,506 Schlumberger Sept. 29, 1936 2,587,243 Sweetman Feb. 26, 1952 2,638,323 Bannon May 1K2, 1953 Man- AM- M 

